Fire retardant potential of natural fiber reinforced polymer composites: a review

This review examines the fire retardant potential of natural fiber-reinforced polymer composites derived from plant fibers such as sisal, jute, hemp and coir etc. While these materials offer eco-friendly and cost-effective advantages, their inherent flammability remains a concern. The study consolidates various methodologies employed in evaluating the fire performance of these composites, encompassing cone calorimetry, Limiting Oxygen Index (LOI) test, UL-94 vertical burning test, Thermal Gravimetric Analysis (TGA), and smoke density test, which have been extensively discussed in prior literature. However, despite this coverage, there exists a gap in the lack of standardized evaluation methods and comprehensive studies addressing real-world conditions. To address these gaps, this review critically analyzes the existing research landscape and proposes strategies for improvement. It emphasizes the necessity for standardized testing protocols and comparative studies using uniform methodologies to enable direct comparisons among studies. Furthermore, the review suggests investigating the effects of environmental factors (humidity, temperature, UV exposure, and aging) on fire resistance and emphasizes longitudinal studies to assess the stability and durability of fire retardant treatments over extended periods. Additionally, it explores emerging eco-friendly fire retardant materials and nanotechnologies, highlighting their potential to enhance flame retardancy in natural fiber-reinforced polymer composites, while calling for further evaluation of their efficacy, compatibility, and environmental impact in future research endeavors. Through this, the review aims to bridge the gap between existing knowledge and practical application in improving the fire retardant properties of these composites for sustainable and safer material development.